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Aerospace and Electronic Systems, IEEE Transactions on

Issue 2 • Date April 2005

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Displaying Results 1 - 25 of 38
  • Mixed H2/H filtering for uncertain systems with regional pole assignment

    Publication Year: 2005 , Page(s): 438 - 448
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2828 KB) |  | HTML iconHTML  

    The mixed H2/H filtering problem for uncertain linear continuous-time systems with regional pole assignment is considered. The purpose of the problem is to design an uncertainty-independent filter such that, for all admissible parameter uncertainties, the following filtering requirements are simultaneously satisfied: 1) the filtering process is asymptotically stable; 2) the poles of the filtering matrix are located inside a prescribed region that compasses the vertical strips, horizontal strips, disks, or conic sectors; 3) both the H2 norm and the H norm on the respective transfer functions are not more than the specified upper bound constraints. We establish a general framework to solve the addressed multiobjective filtering problem completely. In particular, we derive necessary and sufficient conditions for the solvability of the problem in terms of a set of feasible linear matrix inequalities (LMIs). An illustrative example is given to illustrate the design procedures and performances of the proposed method. View full abstract»

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  • Decision fusion rules in multi-hop wireless sensor networks

    Publication Year: 2005 , Page(s): 475 - 488
    Cited by:  Papers (50)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1518 KB) |  | HTML iconHTML  

    The decision fusion problem for a wireless sensor network (WSN) operating in a fading environment is considered. In particular, we develop channel-aware decision fusion rules for resource-constrained WSNs where binary decisions from local sensors may need to be relayed through multi-hop transmission in order to reach a fusion center. Each relay node employs a binary relay scheme whereby the relay output is inferred from the channel impaired observation received from its source node. This estimated binary decision is subsequently transmitted to the next node until it reaches the fusion center. Under a flat fading channel model, we derive the optimum fusion rules at the fusion center for two cases. In the first case, we assume that the fusion center has knowledge of the fading channel gains at all hops. In the second case, we assume a Rayleigh fading model, and derive fusion rules utilizing only the fading channel statistics. We show that likelihood ratio (LR) based optimum decision fusion statistics for both cases reduce to respective simple linear test statistics in the low channel signal-to-noise ratio (SNR) regime. These suboptimum detectors are easy to implement and require little a priori information. Performance evaluation, including a study of the robustness of the fusion statistics with respect to unknown system parameters, is conducted through simulations. View full abstract»

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  • Emitter localization using clustering-based bearing association

    Publication Year: 2005 , Page(s): 525 - 536
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1022 KB) |  | HTML iconHTML  

    A closed-form emitter location estimator using time difference of arrival (TDOA) measurements is developed based on triangulation of hyperbolic asymptotes. The problem of associating the asymptotes with the emitter is solved by clustering the bearing angles of the linear asymptotes using a kernel density estimate. A closed-form estimate of the emitter location is obtained from triangulation of the clustered bearings using a weighted version of the pseudolinear estimator. By way of simulation examples, the proposed closed-form estimator is shown to outperform the computationally demanding and divergence-prone maximum likelihood (ML) estimator at moderate TDOA noise levels. View full abstract»

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  • Single-event performance of COTS-based MPU under flare and nonflare conditions

    Publication Year: 2005 , Page(s): 599 - 607
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (7751 KB) |  | HTML iconHTML  

    We investigated the in-orbit performance of a high-performance on-board computer developed with commercial off-the-shelf (COTS) technology in terms of its performance during the occurrence of single event effects. The processor worked and performed successfully both under normal and under solar flare conditions in 800 km altitude polar orbit. During a solar flare, the occurrence of single events increased by a factor of more than four compared with normal conditions. The area where single events occurred during the solar flare spread to the polar region, whereas normally they are limited to the region of South-Atlantic anomalies (SAA). Our results suggest that the performance of our COTS processor is sufficient for future space applications. View full abstract»

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  • Reduced state estimators for consistent tracking of maneuvering targets

    Publication Year: 2005 , Page(s): 608 - 619
    Cited by:  Papers (5)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (378 KB) |  | HTML iconHTML  

    Linear Kalman filters, using fewer states than required to completely specify target maneuvers, are commonly used to track maneuvering targets. Such reduced state Kalman filters have also been used as component filters of interacting multiple model (IMM) estimators. These reduced state Kalman filters rely on white plant noise to compensate for not knowing the maneuver - they are not necessarily optimal reduced state estimators nor are they necessarily consistent. To be consistent, the state estimation and innovation covariances must include the actual errors during a maneuver. Blair and Bar-Shalom have shown an example where a linear Kalman filter used as an inconsistent reduced state estimator paradoxically yields worse errors with multisensor tracking than with single sensor tracking. We provide examples showing multiple facets of Kalman filter and IMM inconsistency when tracking maneuvering targets with single and multiple sensors. An optimal reduced state estimator derived in previous work resolves the consistency issues of linear Kalman filters and IMM estimators. View full abstract»

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  • Comparison of detectability of traditional pulsed and spread spectrum radar waveforms in classic passive receivers

    Publication Year: 2005 , Page(s): 746 - 751
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (258 KB) |  | HTML iconHTML  

    Passive receivers can be used to detect radar emissions over considerable distances. If range resolution requirements are fixed, it is of interest to compare the detectability of equal-bandwidth/equal-energy waveforms regardless of their time duration. Relative detection ranges are predicted, via computer simulation, for two types of transmitted waveforms: a benchmark rectangular pulse and a Welti binary coded waveform. The waveforms will be detected by square-law, delay and multiply, wideband, and channelized passive receivers possessing typical bandwidth, noise-floor, and loss parameters. A comparison is given showing the relative low probability of intercept and low probability of detection (LPI/LPD) attributes of each waveform and the relative detection attributes of each receiver. View full abstract»

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  • Active transmitting phased antenna arrays

    Publication Year: 2005 , Page(s): 407 - 420
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (14577 KB) |  | HTML iconHTML  

    The benefits of using transmitting phased array antennas for radar systems are examined. Accurate performance prediction for the transmitting phased array antennas requires theories describing both the antenna system and the power generation devices. These theories were created and applied to the design and performance evaluation of the Russian 3-D mobile solid-state surveillance radar 67N6E (GAMMA-DE), a PAA designed for long-range air defense. View full abstract»

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  • Optimal dwell time for approach-warning radar

    Publication Year: 2005 , Page(s): 723 - 728
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (199 KB) |  | HTML iconHTML  

    An analysis of radar signals is provided with details appropriate in the design of short range long dwell time radar systems, e.g. missile warning radar. It considers nonuniform amplitude return details from target range translation during long dwell times and provides an expression for dwell time that optimizes signal-to-noise ratio (SNR). View full abstract»

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  • M. Barry Carlton Award for 2002 - Karl Gerlach

    Publication Year: 2005 , Page(s): 768
    Save to Project icon | Request Permissions | PDF file iconPDF (524 KB)  
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  • Orbit ephemeris monitors for local area differential GPS

    Publication Year: 2005 , Page(s): 449 - 460
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1674 KB) |  | HTML iconHTML  

    Methodologies sufficient to monitor GPS satellite orbit ephemeris for category I aircraft precision approach navigation are described. In the absence of a satellite maneuver, it is shown that a monitor based on the projection of previously validated ephemeris parameters is adequate to meet navigation integrity and availability requirements. After scheduled stationkeeping maneuvers, no previously validated ephemerides are available, so a measurement-based method is required. The feasibility of such a monitor is also established. View full abstract»

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  • Practical stabilization in attitude thruster control

    Publication Year: 2005 , Page(s): 584 - 598
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (956 KB) |  | HTML iconHTML  

    The attitude stabilization of a spacecraft using thrusters is considered from a practical point of view, i.e., when actuator constraints, uncertainties and failures, measurement noise, fuel consumption, and inertia matrix uncertainty are considered. A variable structure controller based on sliding modes is obtained first, which guarantees global exponential stability under actuator constraints, uncertainties, and failures. The design is based on a continuous average-proportional torque selection function and a set of feasible sliding surfaces, which may be adapted to improve performance. Exponential convergence towards ultimate bounds is guaranteed when all other practical issues arise. View full abstract»

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  • Nonparametric rank detectors under K-distributed clutter in radar applications

    Publication Year: 2005 , Page(s): 702 - 710
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (290 KB) |  | HTML iconHTML  

    This correspondence deals with a comparative analysis of parametric detectors versus rank ones for radar applications, under K-distributed clutter and nonfluctuating and Swerling II target models. We show that the locally optimum detectors (LODs) (optimum for very low signal-to-clutter ratio (SCR)) under K-distributed clutter are not practical detectors; on the contrary, asymptotically optimum detectors (optimum for high SCR) are the practical ones. The performance analysis of the parametric log-detector and the nonparametric (linear rank) detector is carried out for independent and identically distributed (IID) clutter samples, correlated clutter samples, and nonhomogeneous clutter samples. Some results of Monte Carlo simulations for detection probability (Pd) versus SCR are presented in curves for different detector parameter values. View full abstract»

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  • RFNN control for PMLSM drive via backstepping technique

    Publication Year: 2005 , Page(s): 620 - 644
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2597 KB) |  | HTML iconHTML  

    A robust fuzzy neural network (RFNN) control system is proposed in this study to control the position of the mover of a permanent magnet linear synchronous motor (PMLSM) drive system to track periodic reference trajectories. First, an ideal feedback linearization control law is designed based on the backstepping technique. Then, a fuzzy neural network (FNN) controller is designed to be the main tracking controller of the proposed RFNN control system to mimic an ideal feedback linearization control law, and a robust controller is proposed to confront the shortcoming of the FNN controller. Moreover, to relax the requirement for the bound of uncertainty term, which comprises a minimum approximation error, optimal parameter vectors and higher order terms in Taylor series, an adaptive bound estimation is investigated where a simple adaptive algorithm is utilized to estimate the bound of uncertainty. Furthermore, the simulated and experimental results due to periodic reference trajectories demonstrate that the dynamic behaviors of the proposed control systems are robust with regard to uncertainties. View full abstract»

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  • Estimation and classification of FM signals using time frequency transforms

    Publication Year: 2005 , Page(s): 421 - 437
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3753 KB) |  | HTML iconHTML  

    This work deals with electronic warfare: we have to process an intercepted radar-emitted signal assumed to be frequency-modulated (FM). A battery of parametric models being available, we face the two main problems: the parameter estimation, given a model, and the classification, given the battery. For the former, we propose the classical maximum likelihood estimator (MLE) and an original numerical scheme to reach it. For the latter, we construct a test based on the estimated variances cross-ratios. Both perform very efficiently with respect to (w.r.t.) the Cramer-Rao lower bound (CRLB) and the rate of correct classification, respectively, for low signal-to-noise ratios (SNRs). View full abstract»

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  • Particle filters for tracking with out-of-sequence measurements

    Publication Year: 2005 , Page(s): 693 - 702
    Cited by:  Papers (27)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (269 KB) |  | HTML iconHTML  

    An extension is presented to the particle filtering toolbox that enables nonlinear/non-Gaussian filtering to be performed in the presence of out-of-sequence measurements (OOSMs) with arbitrary lag, without the need to adopt linearising approximations in the filter and without the degradation of performance that would occur if the OOSMs were simply discarded. An estimate of the performance of the OOSM particle filter (OOSM-PF) is obtained for bearings-only tracking scenarios with a single target and a small number of sensors. These performance estimates are then compared with the posterior Cramer-Rao lower bound (CRLB) for the state estimate rms error and similar performance estimates obtained from the oosm extended Kalman filter (OOSM-EKF) algorithms recently introduced in the literature. For a mildly nonlinear bearings-only tracking problem the OOSM-PF and OOSM-EKF are shown to achieve broadly similar performance. View full abstract»

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  • Comparison of low angle radar clutter models

    Publication Year: 2005 , Page(s): 736 - 746
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (361 KB) |  | HTML iconHTML  

    Three low angle clutter models, the compound-K, the noncentral gamma-gamma (NCGG), both of which model speckle, and the Weibull distributions are compared. The derivations of the first two densities are surprisingly similar, differing on only one critical point. The compound-K assumes that the Gaussian random variables that are the input to the square law detector have zero means, while the NCGG assumes that the Gaussian random variables have nonzero means. The compound-K must then assume that it is the output variance that is fluctuating to produce speckle, while the NCGG assumes that it is the noncentrality parameter, resulting from the addition of the nonzero means that is fluctuating. The difference in the resulting models is significant. The Weibull density has long been used to model clutter successfully, and it too will be considered for comparison, but its use is not based upon a physically motivated development. Rather, its use is based on comparisons of clutter output densities being well matched by the Weibull density with appropriate parameters. View full abstract»

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  • Terrain database integrity monitoring for synthetic vision systems

    Publication Year: 2005 , Page(s): 386 - 406
    Cited by:  Papers (4)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6951 KB) |  | HTML iconHTML  

    A real-time terrain database integrity monitor for synthetic vision systems (SVS) that are to be used in civil aviation is presented. SVS provides pilots with advanced display technology including terrain information as well as other information about the external environment such as obstacles and traffic. The use of SVS to support strategic and tactical decision-making and the compelling nature of the terrain depiction may require terrain database server certification at the essential and flight-critical levels. SVS and terrain database characteristics are discussed and a failure model is identified. Real-time integrity monitors are proposed that check the consistency between terrain profiles described by the database and terrain profiles that are sensed in flight by either a downward-looking (DWL) sensor or a forward-looking (FWL) season A DWL sensor scheme is discussed in detail and it is shown that this scheme can provide the necessary integrity required for an essential certification of a terrain database server. View full abstract»

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  • Self-oscillating DC-to-DC switching converters with transformer characteristics

    Publication Year: 2005 , Page(s): 710 - 716
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (930 KB) |  | HTML iconHTML  

    Fourth-order converters with both input and output filters are analyzed in self-oscillating sliding mode. The boost converter with output filter and the Cuk converter are shown to have stable dynamics and an equilibrium point with transformer characteristics. The analytical predictions are verified by experimental results. View full abstract»

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  • Robust estimation of radar reflectivities in multibaseline InSAR

    Publication Year: 2005 , Page(s): 751 - 758
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (276 KB) |  | HTML iconHTML  

    We examine how to reliably exploit baseline diversity of a multichannel interferometric synthetic aperture radar (InSAR) system to overcome the layover problem. In practice, the baseline steering vectors will be imprecise, resulting in array miscalibration. We propose a nonparametric multilook approach based on robust Capon beamforming (RCB), allowing for uncertainty in the steering vectors. View full abstract»

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  • A quantization architecture for track fusion

    Publication Year: 2005 , Page(s): 671 - 681
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (407 KB) |  | HTML iconHTML  

    Many practical multi-sensor tracking systems are based on some form of track fusion, in which local track estimates and their associated covariances are shared among sensors. Communication load is a significant concern, and the goal of this paper is to propose an architecture for low-bandwidth track fusion. The scheme involves intelligent scalar and vector quantization of the local state estimates and of the associated estimation error covariance matrices. Simulation studies indicate that the communication saving can be quite significant, with only minor degradation of track accuracy. View full abstract»

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  • Aeronautical telemetry using offset QPSK in frequency selective multipath

    Publication Year: 2005 , Page(s): 758 - 767
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (728 KB) |  | HTML iconHTML  

    The impact of frequency selective multipath fading on the bit error rate performance of ARTM Tier-1 waveforms (FQPSK and SOQPSK) is derived and analyzed. In the presence of a strong specular reflection with relative magnitude |Γ1|, the ARTM Tier-1 waveforms suffer a loss in performance of (1 - |Γ1|)-4√|Γ1| for |Γ1| < 0.5 and a relatively high error floor at approximately 10-2 for |Γ1| ≥ 0.5. The ARTM Tier-1 waveforms possess twice the spectral efficiency of PCM/FM, but exhibit a greater loss and higher error floors than PCM/FM for the same multipath conditions and signal-to-noise ratio. View full abstract»

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  • Target classification approach based on the belief function theory

    Publication Year: 2005 , Page(s): 574 - 583
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1374 KB) |  | HTML iconHTML  

    A theoretical framework is presented for target classification based on the belief theory on the continuous space. The proposed approach is applicable when class-conditioned densities of feature/attribute measurements are known only partially, as subjective models of a potential "betting" behaviour. Prior class probabilities may also be unknown. Numerical examples are provided to illustrate how the proposed approach is more cautious in decision making and produces very different results from those obtained using the Bayesian classifier. View full abstract»

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  • Efficient robust AMF using the FRACTA algorithm

    Publication Year: 2005 , Page(s): 537 - 548
    Cited by:  Papers (7)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3929 KB) |  | HTML iconHTML  

    The FRACTA algorithm has been shown to be an effective space-time adaptive processing (STAP) methodology for the airborne radar configuration in which there exists nonhomogeneous clutter, jamming, and dense target clusters. Further developments of the FRACTA algorithm are presented here in which the focus is on the robust, efficient implementation of the FRACTA algorithm. Enhancements to the FRACTA algorithm include a censoring stopping mechanism, an alternative data blocking approach for adaptive power residue (APR) censoring, and a fast reiterative censoring (RC) procedure. Furthermore, a coherent processing interval (CPI) segmentation scheme for computing the adaptive weights is presented as an alternative approach to computing the adaptive matched filter (AMF) weight vector that allows for lower sample support and reduced computational complexity. The enhanced FRACTA algorithm, denoted as FRACTA.E, is applied to the KASSPER I challenge datacube which possesses dense ground target clusters that are known to have a significant deleterious effect on standard adaptive matched filtering (AMF) processors. It is shown that the FRACTA.E algorithm outperforms and is considerably more computationally efficient than both the original FRACTA algorithm and the standard sliding window processing (SWP) approach. Furthermore, using the KASSPER I datacube, the FRACTA.E algorithm is shown to have the same detection performance as the clairvoyant algorithm where the exact range-dependent clutter covariance matrices are known. View full abstract»

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  • Analysis of CGSDS file delivery protocol: immediate NAK mode

    Publication Year: 2005 , Page(s): 503 - 524
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2983 KB) |  | HTML iconHTML  

    We analyze the immediate negative acknowledgment (NAK) mode of the consultative committee for space data systems (CCSDS) file delivery protocol for the single-hop file transfer operation. We propose a timer setting rule that minimizes the expected time taken to transfer a file under the constraint that the throughput efficiency is maximized. Then, we derive the expected file delivery time and compare it with that of the deferred NAK mode. The main contribution is the closed-form expression for evaluating the performance metrics. View full abstract»

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  • Impact of Van Jacobson header compression on TCP/IP throughput performance over lossy space channels

    Publication Year: 2005 , Page(s): 681 - 692
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (658 KB) |  | HTML iconHTML  

    The impact of Van Jacobson header compression (VJHC) on the throughput performance of Transmission Control Protocol/Internet Protocol (TCP/IP) over lossy space channels is studied in an experimental manner using a test-bed. The experimental results show that VJHC benefits the transmission at bit error rates (BERs) around 10-6 or less, but also results in performance degradation in an environment with higher BER. View full abstract»

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Aims & Scope

IEEE Transactions on Aerospace and Electronic Systems focuses on the equipment, procedures, and techniques applicable to the organization, installation, and operation of functional systems designed to meet the high performance requirements of earth and space systems.

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Meet Our Editors

Editor-in-Chief
Lance Kaplan
Army Research Laboratory